Laundry prespotters have long been known and used to treat fabric stains which resist the usual washing processes. The advent and increasing use of hydrophobic synthetic fibers in place of cotton has created a need for improved stain treatments to combat the affinity of such fibers for greasy soils as well as other wash resistant soils. The application of permanent press finishes to cotton and cotton blends also has accentuated the need for effective prespotters designed for removal of a multiplicity of grease and food based stains.
Prior art prespotters in the form of liquids, powders, aerosols and sticks are known.
Liquids containing specific chemical reagents acting to decolorize or remove certain stains by means of chemical reaction on the stain are known (e.g., the familiar two solution "ink eradicator"), as are solid sticks containing specific chemicals or solvents to react with or dissolve specific stains. None of these stain removers are effective agianst a wide spectrum of stains.
Liquid laundry detergents have been recommended for direct application to heavily soiled areas. Laundry bar soaps and dry powdered detergents have been similarly recommended for application to moistened soiled fabrics. Dry products, some containing enzymes, having been marketed for use with water to form a pre-soak solution in which heavily stained articles are immersed for a time prior to laundering. Each of the foregoing suffer from the disadvntage of inconvenience in use, need for dilution with water with accompanying loss of effectiveness, tendency to spill, tendency to contact the skin, danger of accidental ingestion or failure to affect a broad spectrum of stains.
Aerosol prespotters, some containing enzymes, are known, but these suffer the disadvantages common to aerosols such as flammability, inhalation danger, depletion of atmospheric ozone, and the problem of safe disposal of empty containers.
Liquid prespotters, some containing enzymes, are known but these share with the other liquids mentioned above inconvenience in use, tendency to spill, and danger of accidental ingestion.